<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
    <input type="test" value="" >
    <button onclick="Calculater()">计算</button>
    <script>
        

        function Calculater(){
            let a = prompt("输入第一个数字")
            let b = prompt("输入第二个数字")
            let c = prompt("输入运算符")
            let d = eval(a+c+b)
            alert(a+c+b+ "="+d )
        }
    </script>
</body>
</html>